Boko Haram gunmen killed more than 50 people in three separate attacks, including two near Chibok, the Nigerian town were the Islamists kidnapped more than 200 schoolgirls last month, witnesses have said.
The first attack on Monday afternoon killed 10 in the village of Shawa, some seven
kilometres (4.3 miles) from Chibok, in northeastern Borno state, a number of residents said on condition of anonymity.

Gunmen then stormed the nearby village of Alagarno late on Tuesday and stole food, razed homes and fired on fleeing civilians.

"It was a sudden attack," said resident Haruna Bitrus, in an account supported by other locals.

"They began shooting and set fire to our homes. We had to flee to the bush. They killed 20 of our people," he added.

Many of those who fled the Alagarno attack ran to Chibok, where Boko Haram seized 276 schoolgirls on April 14. A total of 223 are still missing.

In the third attack, suspected militants killed at least 25 people in a raid on Chukongudo, on the shores of Lake Chad, at about 1pm (1200 GMT) on Wednesday.

About a dozen heavily armed gunmen in two vehicles stormed the farming village, opening fire on residents and burning more than 300 homes, effectively razing it to the ground.

"They came in broad day light and attacked the village with guns and bombs," said Chukongudo resident Zarani Alide.

"They burnt the whole village and killed 25 people", added Alide, who said he fled to Gamboru Ngala town 20 kilometres away.

Gamboru Ngala was the scene of a deadly Boko Haram raid two weeks ago in which up to 300 people were reported killed and scores of homes and a market were burnt.

Alide said the militants had warned residents to evacuate the village or be attacked. Some left but others stayed until soldiers stationed there were withdrawn 10 days ago.

Nigeria's military said it had deployed heavily to the Chibok area to find the girls but 223 girls who remain in captivity.

Local residents in the affected villages claimed troops, however, had not responded to the attacks.

"While the gunmen were fleeing, three of their vehicles broke down and they have stayed behind to fix them. They were there up to this morning" with no response from the military, said Bitrus.

Borno has been worst affected by the five-year insurgency and is under a state of emergency with two neighbouring states. Nigeria's parliament approved a six-month extension to special powers on Tuesday.